move_rename_dupes

#!/bin/bash

usage() {
    echo "Moves all files and directories from source_path to dest_path."
    echo "If a file exists in dest_path then the new file from source_path will be renamed (name.ext -> name_dup.ext)."
    echo "For dry run (print the commands but not run them) pass the '-dry' option."
    echo -e "\nUsage:\n$0 [-dry] source_path dest_path"
    exit 1
}

if [[ $# -eq 3 ]] ; then
    if [[ $1 != "-dry" ]] ; then
      usage
    fi
    dry="$1"
    src="$(readlink -m "$2")"
    dst="$(readlink -m "$3")"
elif [[ $# -eq 2 ]] ; then
    src="$(readlink -m "$1")"
    dst="$(readlink -m "$2")"
else
  usage
fi

if [ -z $dry ] ; then
  my_mkdir='mkdir'
  my_mv='mv'
else
  my_mkdir='echo mkdir'
  my_mv='echo mv'
fi

find "$src" -type f -print0 | 
while IFS= read -r -d '' file; do
  target="${dst}/${file#${src}/}"

  # bash parameter expansion (%%, ##, etc.): https://stackabuse.com/guide-to-parameter-expansion-in-bash/
  source_last_dir="$(basename "$(dirname "$file")"%%/)"
  source_last_dir="${source_last_dir%%/}"
  target_last_dir="$(basename "$(dirname "$target")"%%/)"
  target_last_dir="${target_last_dir%%/}"
  target_dir="$(dirname "$target")"
  target_dir="${target_dir%%/}"
  filename="$(basename "$target" "$fullfile")"

  if [ "$source_last_dir" == "$target_last_dir" ]; then
    target_dir="${target_dir}_dup"
    target="${target_dir}/$filename}"
  fi;

  echo "\"target_dir=$target_dir\""
  echo "\"target=$target\""

  #echo "forgi1 target=$target"
  #echo "forgi2 dst=$dst"
  #echo "forgi3 file=$file"
  #echo "forgi4 src=$src"
  #echo "\"source_last_dir=$source_last_dir\""
  #echo "\"target_last_dir=$target_last_dir\""


  if [[ ! -e "$target" ]]; then 
    if [[ -z "$target_dir" ]]; then 
      $my_mkdir -p "$$target_dir"
    fi
    $my_mv "$file" "$target"
  else 
    extension="${filename##*.}"
    filename="${filename%.*}_dup"
    $my_mv "$file" "$target_dir/$filename.$extension"
  fi; 
done